Catalytic production of polyhalo-keto-alkenoic acids

ABSTRACT

1. A METHOD FOR PRODUCING C5 TO C10 POLYCHLORINATED OR POLYBROMINATED 4-KETO-ALKENOIC ACIDS, WHICH COMPRISES THE STEPS OF DIRECT COMBINED CATALYTIC HALOGENATION AND DEHYDROGENATION OF C5 TO C10 4-KETO MONOCARBOXY ALKANOIC ACIDS WITH ELEMENTAL CHLORINE OR BROMINE IN THE PRESENCE OF A CATALYST AMOUNT OF AT LEAST ONE CATION SELECTED FROM THE GROUP CONSISTING OF ALUMINUM, ZINC, TITANIUM, COBALT, MAGNESIUM AND CALCIUM, WHEREIN THE REACTION IS INITATED AT SUBSTANTIALLY AMBIENT TEMPERATURE AND SURING SAID TIME PERIOD THE TEMPERATURE IS GRADUALLY RAISED TO A FINAL TEMPERATURE OF FROM 170*C. TO 210*C, THE REACTION BEING CONTROLLED BY THE RATE OF CHLORINE OR BROMINE SUFFICIENT TO PREVENT THE TEMPERATURE EXCEEDING 210*C.

United States Patent 3,842,126 CATALYTIC PRODUCTION OF POLYHALO-KETO-ALKENOIC ACIDS William A. Erby, Alburtis, and James F. Tompkins,Allentown, Pa., assignors to Air Products and Chemicals, Inc.,Philadelphia, Pa.

No Drawing. Continuation of abandoned application Ser. No. 723,283, Apr.22, 1968. This application Sept. 26, 1972, Ser. No. 292,384

Int. Cl. C07c 59/18 US. Cl. 260-539 R 9 Claims ABSTRACT OF THEDISCLOSURE Halogenation of C -C saturated keto mono-carboxy acids ortheir acidogenic derivatives with elemental halogen in the presence ofcertain catalysts to yield olefinic halogenated compounds (e.g. acidsand lactones) containing at least four halogen atoms per molecule isdisclosed. The catalyst selected depends upon the particular end productdesired. Halogenated products of the process are useful as insecticides,plant growth control agents and defoliants. Particularly useful productsare those olefinic polychlorinated derivatives of 4-keto-pentanoic acidwhich contain at least four chlorine atoms per molecule such as, forexample, 2,3,5,5,5-pentachl0ro-4-ket0 pentenoic acid.

This is a continuation of application Ser. No. 723,283, filed Apr. 22,1968, now abandoned.

BACKGROUND OF THE INVENTION (1) Field of the Invention The presentinvention is concerned with novel methods for the catalytic synthesis ofpolyhalogenated and perhalogenated keto alkenoic acids, such as, forexample, halogenated C to C mono-carboxylic acids; from thecorresponding saturated keto acids, their esters, amides, anhydrides,lactones, acyl halides, and other acidogenic derivatives. Moreparticularly, it pertains to methods of catalytically chlorinating and/or brominating 4-ketopentanoic acids and their derivatives to obtainacyclic and cyclic olefinic products which contain at least 4 halogenatoms per molecule.

(2) Description of the Prior Art While various investigators havereported the chlorination of 4-keto C, to C acids to the mono ordichloro stage, there is no report to date of any direct combinedchlorination and dehydrogenation of such acids (or their acidogenicderviatives) to the unsaturated polyhalogenated or perhologenated stage.As used herein, the terms polyhalogenated and polychlorinated refer,respectively, to compounds containing at least four halogen atoms permolecule (which may be of the same or of different halogens) and tocompounds which contain at least four chlorine atoms per molecule. Theterms perhalogenated and perchlorinated refer, respectively, tocompounds in which all of the hydrogen atoms attached to carbon atoms inthe molecule are substituted with halogen atoms (which may be of thesame or different halogens), and to compounds in which all of thehydrogen atoms attached to carbon atoms are substituted with chlorineatoms. The term halogen is intended to include chlorine, bromine orcombinations thereof.

A common 4-keto-pentanoic acid, which is available in commerce, islevulinic acid. Early attempts to chlorinate levulinic acid directlyresulted only in the production of mono and dichloro derivatives.[Seissl, Annallen, 249, 288303 (1888).] A number of polychloro-pentenoylketones, acids, acid halides, and anhydrides have 3,842,126 PatentedOct. 15, 1974 since been prepared by methods other than by the directchlorination of levulinic acid [Zincke, Berichte der Deutsche ChemischeGessellschaft, 23, 240 (1890); 24, 916 (1891); 25, 2221 (1892); 26, 506(1893); and 26, 317 (1893)].

US. Pat. No. 3,275,505 does disclose the direct halogenation oflevulinic acid. However, the reaction temperatures are between and C.and, even with high degrees of halogenation, no more than four atoms ofhalogen are added per molecule of levulinic acid. Further, there is noconversion of the acid from a saturated to an olefinic compound.

BRIEF SUMMARY OF THE INVENTION Briefly summarized, the inventionpertains to the catalytic halogenation, particularly with chlorine, ofsaturated 4-keto mono-carboxylic acids of which levulinic acid is aprime example. While the invention may be utilized in connection witheither chlorine or bromine or both, those compounds produced fromchlorine and/ or bromine and levulinic acid are possessed of particularutility in connection with growth control of plants and in insecticidalapplications. One particular compound, which can be made by processes ofthe invention, and which is designated 2,3,5,5,5-pentachloro-4-ketopentenoic acid has a unique capacity for wilting the foliage of woodyjungle plants such as cotton. This characteristic is the basis for anovel method of harvesting cotton which is described in co-pendingapplication Ser. No. 632,937 entitled Method of Harvesting Cotton, nowUS. Pat. No. 3,472,004. Further, chlorinated compounds of the inventionare of value as jungle defoliants. Other uses of the compounds which maybe made by the instant process are described in the co-pendingapplication Ser. No. 541,096 entitled Preparation and Use of PolychloroKeto-Alkenoic Acids now US. Pat. No. 3,557,546.

In most general terms, the invention contemplates the catalyticchlorination and/or bromination of saturated 4-keto mono-carboxylicacids or their acidogenic derivatives (e.g. esters, amides, etc.) withelemental halogen over relatively long periods of time and at elevatedtemperatures. Since the reactions are exothermic, it is usuallypreferred to halogenate at rates which prevent violent fluctuations oftemperature such as would cause product degradation or undue increase inby-product formation. When batch processes are used, it is preferred toraise reaction temperatures gradually as the reaction proceeds over aperiod of time to the maximum limits.

Conditions utilized are always severe enough to cause bothdehydrogenation and the addition of at least four halogen atoms permolecule of acid. Under more severe conditions, additional halogen maybe incorporated to reach the perhalogenated state and, further, to causeformation of cyclic compounds.

The catalysts used in connection with the invention are limited to thecations iron, aluminum, zinc, titanium, cobalt, magnesium and calcium.While it is often most convenient to introduce the catalysts as salts,preferably chlorides, such salts need not be utilized as the source ofthe desired cation. In some instances the elemental metal may beutilized in the form of shavings or filings and the catalyst, in effect,formed in situ due to the reaction with halogen. Thus, when the termcation is used herein it is intended to encompass all sources of thecations and all means for introducing them into the reactionenvironment.

The amount of catalyst used, calculated as the chloride, and stated asweight percent of the 4-keto mono-carboxylic acid or acidogenic materialmay vary from .1-15 with a range of from 510% being generally preferred.In any event the catalytic amount necessary to optimize the reactionvaries with reactants and reaction parameters but can, nonetheless, bereadily determined by those skilled in the art.

The reactions can best be illustrated with respect to the chlorinationof levulinic acid and the summary discussion which follows is generallyrelated to the examples in the discussion of the preferred embodimentsbelow. These embodiments utilize levulinic acid or acidogenicderivatives thereof.

(21) Iron Catalyst: Iron cation, preferably introduced as FeCl has aunique effect on the reaction. Its use leads selectively to theproduction of 2,3,4,5,5,5-hexachloro-2- pentenoyl-4-lactone attemperatures as low as 155 C. and reaction times as short as 8 hours.The lactone may be hydrolyzed, preferably in the presence of chlorine,to yield 2,3,5,5,S-pentachloro-4-keto-pentenoic acid. By-products of thechlorination reaction are dichloro maleic anhydride (which is removedduring hydrolysis) and some penta chloro lactones (which are alsoconverted to the pentenoic acid during hydrolysis).

(b) Aluminum and Other Catalysts: Particular cations selected from thegroup consisting of aluminum, zinc, titanium, cobalt, magnesium andcalcium which may be introduced, for example, respectively, as aluminumchloride, zinc chloride, titanium tetrachloride, cobaltic chloride,magnesium chloride and calcium chloride, cause the reaction to followstill another course. When these catalysts are used, a high yield oftetrachloro-4-keto-pentenoic acid (e.g. 3,5,5,5-tetrachloro-4-ketopentenoic acid) is obtained by reacting levulinic acid with chlorine forabout 3 hours at temperatures below 140 C. With the continuation ofchlorination and the raising of the temperature above 150 C. (preferably155 C.), there is quantitative conversion of the product to2,3,5,5,5-pentachloro-4-keto pentenoic acid after a period of about 20to 30 hours. The purity of the product obtained in this manner iscomparable to that obtained when the lactone produced in the ferricchloride catalyzed reaction is hydrolyzed.

The above reactions may be conducted with bromine instead of chlorine.Further, a reaction may be begun with one type of halogen, discontinuedbefore perhalogenation is completed, and reacted with yet anotherhalogen to the completion of halogenation so that a given molecule willcontain atoms of different halogens.

The halogenated compounds produced by the novel method of the presentinvention from 5 carbon keto carboxy acids correspond, in form of thecarboxylic acids or their esters, to the formula:

wherein x is 0 or 1, and R is H or the residue of an esterifying organichydroxy compound, such as an alcohol or phenol.

Compounds corresponding to the above formula are produced in high yieldsand exceptional purity in accordance with the invention by the catalyticchlorination of levulinic acid or its acidogenic derivatives undercontrolled conditions of time and temperature to obtain an olefiniclinkage at the carbon in the position alpha to the carboxy group.Illustrative of the compounds thus obtained and certain derivatives(e.g. esters and salts thereof) are:

ClaCC- =C-C=O 2,3,4,5,5,5-hexachlor0-2-pentenoyl-4-1actone (perchloroangelica lactone) 3,5,5,5-tetrach1oro4-keto-2-pentenoic acid I? IICl3CCCH=7CO-NH4+ Ammonium salt of 2,5,5,5-tctrachloro-4-keto-2-pentenoicacid (7) H I I ll Cl3O-CC=CCO- +HNR1R2Ra wherein R is alkyl and R and Rare each alkyl or hydrogen, these compounds being amine salts of2,3,5,5,5- pentachloro-4-keto-2-pentenoic acid.

The polychloro-compounds so produced have been found to have pronouncedactivity as insecticides, herbicides and cotton defoliants, such that,in a process based upon low cost levulinic acid and chlorine,commercially valuable biologically active chemicals can be produced atlow cost.

Esterification of the free acid can be eifected with monohydric orpolyhydric alcohol. Thus, by reacting compound (1) with pentaerythritol,a mixture comprising monoand diesters may be obtained.

Ammonium and amine salts of the free acids can also be formed byreacting the same, respectively, with ammonia or primary, secondary ortertiary alkyl amines including, for example, dipropyl amine, isopropylamine, N,N-dirnethyl hexadecylamine, N,N-dimethyl octadecylamine,N,N-dimethyl dodecylamine and cocoamine.

Accordingly, it is an object of the invention to provide a methodwhereby catalytic halogenation of C to C saturated keto mono carboxyacids or their acidogenic derivatives at temperatures below 210 C.efiects both halogenation and dehydrogenation.

It is a further object of the invention to provide a direct method ofhalogenation where selectively, dependent upon the catalyst and reactionconditions utilized, as well as the reactants present, one may obtainacyclic halogenated olefinic keto acids or related cyclic compounds bothof which are capable of further reactions such as esterification.

It is additionally an object of the invention to provide processes forthe catalytic halogenation of keto carboxy acids, using catalysts whichselectively yield predetermined end-products, under predictable reactionconditions and times.

These and other objects of the invention will be apparent to thoseskilled in the art from a consideration of the exemplary descriptionwhich follows.

It should be appreciated that neither the abstract of the disclosure northe summary of the invention above is intended to constitute alimitation on its extent. They are inserted merely as aids ininformation retrieval and, therefore, the true scope of the invention isto be determined only by a reasonable interpretation of the appendedclaims in light of the disclosure herein contained.

DESCRIPTION OF PREFERRED EMBODIMENTS The desired compounds are produced,in accordance with the invention, for example, by passing chlorine intolevulinic acid or into an acidogenic derivative of levulinic acid overan extended period of time while raising the temperature gradually fromambient temperature to an ultimate temperature which may be as high as210 C., depending upon the catalyst used. As halogen is added, theactivation energy for subsequent substitutions in creases. Therefore, itis necessary to increase the temperature as the reaction proceeds. Inequivalent continuous processes, cold feed can be added to largeagitated bodies of liquid maintained at optimum temperature and suchfresh feed is, in eifect, gradually raised in temperature.

Premature elevation of temperature can induce decomposition andpolymerization of unsuitable intermediates. However, the thermalstability of the intermediates increases as the halogen contentincreases, which allows the reaction temperature to be safely increasedas halogenation proceeds. Since the reactions are exothermic, once theyhave been initiated, it is important to control the rate of addition ofhalogen so that temperatures will not rise above the capacity forthermal stability of the system in its then current degree ofhalogenation. Briefly, then the rate of addition of halogen is afunction of temperature in practicing the invention.

There are thus obtained in high yield and good purity, polychloro andperchloro keto-pentenoic acids and their derivatives, having four ormore chlorine atoms per molecule. The acids obtained can be readilyconverted to the corresponding salts, esters and amides by methodsgenerally known in the art.

The distinct properties of the compounds obtained by the practice of theinvention which render them useful, and effective as insecticidal andherbicidal compositions, are believed to reside in the simultaneouspresence in the carboxylic compound of the polychloro function combinedwith the effect of the olefinic linkage, and the keto type structure.Despite the high insecticidal activity displayed by these compounds,they are highly selective in their action on plants, whereby they alsohave utility as plant growth control and defoliatin g agents.

The following examples illustrate some embodiments of the invention butare not intended to limit the same. The special results obtained by theuse of the iron cation should be particularly noted.

EXAMPLE 1 One hundred sixteen grams of levulinic acid were placed in areactor equipped with a gas dispersion tube, a stirrer and aheating-cooling mechanism. Ferric chloride hexahydrate (1.35 gm.) wasadded to the levulinic acid. Chlorine was then passed through thedispersion tube into the rapidly stirring mixture. An exothermicreaction occurred, and the temperature was allowed to increase to 100 C.It was maintained at this temperature by adjustment of the coolingmechanism. The reaction was allowed to continue until a decrease in thereaction exotherm was indicated by a drop in the temperature inside thereactor.

On completion of this phase of the reaction, the temperature was slowlyraised to 125 to 130 by increasing the temperature of the mechanism.Care was taken during this operation to prevent darkening of thereaction mixture such as might be caused by raising the temperature toorapidly. Again an exotherm was noted. The chlorine fiow rate during therest of the reaction was maintained fast enough to insure that a smallamount of chlorine was present in the reactor exit gas. The reactor washeld at this temperature until the heat output of the reaction againdecreased.

Upon completion of the second phase, the temperature was again raised to155 C. The reaction was then maintained at 155 C. until completion.Completion of the reaction was confirmed by infrared analysis of thesample. The sample spectrum contained no absorption peak between 2.5 and3.5 microns. A very sharp carbonyl absorption band of high intensityappeared at 5.45 microns. This was accompanied by a small shoulder at5.55 microns. An unsaturation absorption band was also evident at 6.15microns.

The product was thus identified as comprising predominantly 2,3,4,5,5,5hexachloro-2-pentenoyl4-lactone (i.e. perchloro-angelica lactone) havingthe following formula:

Boiling Point 74.5 C./0.2 mm. Hg. Refractive Index, 20/D 1.5465.Density, g./ml. at 20 C 1.6357.

Found Theory Chlorine Content 70.2% 69.8% Carbon Content 20.2% 19.8%Molecular Weight 315 305 Strong characterizing adsorption peaks forinfra-red were at 1835 cm? and 974 cmf Weight recovery on the basis ofthis structure was 94% of theoretical.

Halogenated angelica lactone behaves, in its chemical reactions, as ifit were an acyl halide of the type:

t e t Cla-CC-C=COOC1 Thus, it was readily esterified by reaction withsodium phenoxide to yield the phenyl ester of pentachloro-4-keto-2-pentenoic acid.

EXAMPLE 2 Hydrolytic conversion of the product of Example 1 to2,3,5,5,5-pentachloro-4-keto pentenoic acid was effected as follows:

The reaction product of Example 1 prior to hydrolysis consists primarilyof the lactone and some of said pentenoic acid. Conversion of thelactone to the pentenoic acid was carried out by reducing thetemperature of the product below C. and adding water (in an amount equalto 30% of levulinic acid used). This reaction mixture was then rapidlystirred, while a slow stream of chlorine was passed through the systemwith the temperature maintained at about 100 C.

When this hydrolysis was complete, the carbonyl region of the infraredspectrum of the product showed two bands, one at 5.5 and one at 5.6microns. A broad acid- OH absorption band appeared at 3 microns thusindicating substantially complete conversion to said pentachloro-4-ketopentenoic acid.

The temperature was then allowed to drop to approximately 90 and enoughwater was added to cause phase separation. The water, in the upperlayer, was then siphoned out of the reactor as completely as possible.The product was washed two more times with water and dried. It was,thereafter, identified as 2,3,5,5,5-pentachloro-4- keto pentenoic acid.

The following examples are illustrative of those embodiments of theinvention using cations selected from the group consisting of aluminum,zinc, titanium. cobaltic, magnesium and calcium.

EXAMPLE 3 Levulinic acid (116 gm.) was placed in a reactor equipped witha gas dispersion tube, a stirrer and a heating-cooling mechanism.Anhydrous aluminum chloride (0.6 gm.) was added to the levulinic acid.Chlorine was then passed through the dispersion tube into the rapidlystirring mixture. An exothermic reaction occurred and the temperaturewas allowed to increase to 180 C. It was maintained at this temperatureuntil the infra-red spectra indicated that complete conversion to2,3,5,5,5-pentachloro-4-keto pentenoic acid had occurred.

Additional runs were made, using the same techniques, to determine theeffective amount of AlCl catalyst and it was thus determined thateffective catalyst concentration can vary from 0.1 to 10%. Other runswere made to prove the effectiveness of the above-named specific cationsin the reaction.

EXAMPLE 4- Levulinic acid (116 gm.) was placed in a reactor equippedwith a gas dispersion tube, a stirrer and heatingcooling mechanism.Anhydrous aluminum chloride (5.3 gm.) was added to levulinic acid.Chlorine was then passed through the dispersion tube into a rapidlystirring mixture. An exothermic reaction occurred and the temperaturewas allowed to increase to C. It was maintained at this temperatureuntil the infra-red spectra indicated that complete conversion to2,3,5,5,5-penta-chlo ro-4-keto pentenoic acid had occurred.

In reactions conducted in this manner yields of said pentachloro-4-ketopentenoic acid on the order 90% are generally recognized classes (e.g.Lewis Acid Catalysts) are unsuitable. Further, iron as a catalystresults in the production of specific types of compounds (i.e. lactones)and is atypical of even the unique group of operable catalysts disclosedherein.

common. Some 3.5% of a tetrachloro acid results, with The products ofhalogenation, according to the inventhe balance of the product beinglost by entrainment in tion, are mono-olefinically unsaturated at thetetra-, pentathe exit gas. and hexa-halo levels. Use of the catalystsspecified allows As indicated above, it is possible to control thereacthe reactions to proceed fully at temperatures. below 210 tion toselectively obtain a tetrachloro acid such as, for C. and in relativelyshort times. Further, choice of catalyst example,3,5,5,5-tetrachloro-4-keto pentenoic acid. This favors the production ofpredetermined types of derivais illustrated by the following example.tives.

EXAMPLE 5 The reaction rate, up a certain point, is Etflll'lCtlOIl,inter aha, of the amount of catalyst present. Since Water can To anapparatus equipped with a stlrrer, a Cond nse partially and temporarilydecrease catalyst activity it is and a gas dispersion apparatus wereadded levulinic acid referred to utilize anhydrous reactants andanhydrous and anhydrous aluminum chloride f c Welght catalysts. However,when some water is present, the 0f levulinic The levllllnlc 301dCollialned Somfiinitial reaction period is utilized for ridding thesystem where in the neighborhood of 0.5% water. of w t The reaction isstarted by passing chlorine through Throughout the reaction, temperatureshould be carethe system at the lowest temperature where levulinic acidfully controlled so that the reaction exotherm does not is a liquid. Anexothermic reaction occurs which caus s exceed the desired limit.Otherwise, particularly during the temperature to rise to approximately100 C. T the early stages of halogenation, one obtains only polyreactionmixture is kept at this temperature until the eri od t of a tarry naturexotherm ceases, which is not by a decrease in the tem- Th process ofproducing unsaturated polychloro-4- perature of the reactor. This isaccompanied by a deketo pentenoic acid or its acidogenic derivatives,containcrease in chlorine adsorption by the reaction mixture. ing t l tf hl i atoms per l l h b When these phenomena are noted, the temperaturecan exemplified above starting with levulinic acid. However, then beincreased to 155 C. and held at this temperathe process is not limitedto this starting material. Esters, ture until the decrease in thereaction isotherm is again acyl halides, anhydrides and lactones oflevulinic acid can manifest by a temperature drop. At this point thereacbe used. Further, the monochloro and dichloro derivation mixturecontained substantially 100% 3,5,5,5-tct atives of levulinic acid, knownin the prior at, can be used chloro-4-keto-pentenoic acid as determinedby sampling whether the chlorine is in the alkyl chain, in the acyl andanalysis. Total reaction time was 12 hours to this group or in both.Homologous keto acids and keto acids point. relatable to levulinic acidare similarly polychlorinatable The temperature was then raised toapproximately 180 or perchlorinatable in accordance with the inventionC. and held at this temperature, maintaining the reaction provided theycontain the structure: system saturated with chlorine, until totalconversion to H 2,3,5,5,5-pentachloro-4-keto-pentenoic acid occurred. HI I H Other examples of similar reactions utilizing chlorine, obromineor both in succession as well as a variety of cat alysts and startingmaterials are presented below in tabular form. The manipulativetechniques used were wherein R and R are independently selected from thegenerally similar to those described in Example 1. group consisting ofhydrog n, halogen and lower alkyl.

Max. Total Example temp., time, number Starting acid Halogen Catalyst 0.hours Product 6 L v lini a id C1; F6613 82,3,4,5,5,S-hexachloroA-pcntenoyl lactonc. 7 do C1; ZnCl; 302,3,5,5,5-pentachloro-i-kctopentenoic acid. s -do--- C11 T1014 180 35Do. 9 "do.-. C11 00013 180 40 D0. 10.- .do... 01, MgOh 180 30 Do. 11- do01,. 00012 180 30 Do. 12 4-keto hexano Cl; ZnClz 200 302,3,5,5,6-pentaehloro hexenoic acid. 13.. Lev'ulinic acid. Br; then C1,A1 170 16 2,5,5iztirichloro-3,5-dibromo-4-keto pcntenoic ac 146,6-dimethy1-4-ketoheptanoic C1; AlCla 200 302,3,5,5,6-pentach1oro-6,G-dimethykkketo acid. heptenoic acid. 154-ketohexanoic acid CI; MgClz 200 302,3,5,5,fi-pentachloro-4-ketohexenoic acid. 16 d0 C1, MgClg/AICI; 200 30Do.

AlBr 200 30 2,3,5,5,fi-pentabromo-4-ketohexenoic acid. AlBr; 180 302,3,5,5,5-pentabromoA-ketopentenoic acid. A1 180 30 D0. A1 180 302,3,5,5,5-pcntachloro-4-ketopentenoic acid. Mg 180 30 Do. Mg 180 302,3,5,5,6-pentachloroA-ketohcxenoic acid. Levulinic acid MgClz 160 122,3,5,5,5-pentachloro-4-ketopentcnoic acid.

Direct chlorination of levulinic acid readily forms the Temperaturelimits have been given for the halogenasimple chloro derivative. Thereaction has been shown tion reactions. However, it will be appreciatedby those by others to proceed with increasing difficulty only toconversant with the art that reasonable variations can be thetetfafclllofo Stage- 69 made in the temperature and time of halogenationby P PQ Y We have found that on extended chlorlmeans of which the rateand extent of halogenation and nation, in the presence f selectedcatalysts, at temperadehydrogenation can be Variai For instance While Ei 3? gb g f 3 9 E" and preferz'bly i h chlorination and dehydrogenationof levulinic acid can an m t e Preselrlce O ,excess 6 be achieved in 30hours with reaction temperatures on it is possible to go beyond thispoint. Using methods of 70 the 0rd of C Onmcan b havin a Si nificant theinvention, it is possible to substitute chlorine for four f A u h y 0 cF or more hydrogen atoms and to simultaneously split off 0 i i time m te P P to 210 two hydrogen atoms (as HCI) to Produce a new Speciesachieve a similar degree of chlorination and dehydrogenaof olefinicallyunsaturated derivatives. The catalysts tion in a Somewhat 5110f tertime, though With some 1088 Of operable in the invention are specificand total broad 75 selectivity. Utilizing the route where iron is usedas a catalyst, followed by hydrolysis to the free acid, the loss ofselectively become irrelevant.

After the halogenation reaction described above, the reaction productsmay be further reacted to produce esters, amides and salts. When saltsare desired of those products which are lactones, it is first necessaryto obtain them in their free acid form by hydrolysis. The following areillustrative examples of salt formation:

EXAMPLE 8-1 The product of Example 3 was dissolved in ether (othersuitable solvents include, for example, toluene) and ammonia was slowlybubbled through the solution. An excess of acid was maintained in themedia in order to increase yield. The ammonium salt of2,3,5,5,5-pentachloro-4- keto-Z-pentenoic acid was obtained. A portionof the product was further purified by recrystallization from ethylacetate.

EXAMPLE 8-2 The product of Example 2, subsequent to the hydrolysis step,was subjected to the method of Example S1 and the same ammonium salt wasobtained as from Example S-1.

Salts of the various halogenated keto acids of the invention areobtained by reacting them (in their acid form) with ammonia or organicamines, preferably those containing from 1 to 18 carbons. As usedhenceforth herein, the term organic amines is intended to encompass suchcompounds as well as amines which have been reacted with an alkyleneoxide. Amines which have been utilized in this connection include, forexample, noctylamine, N-oleyl-1,3-propylene diamine, ethylamine, diethylamine, triethylamine, propylamine, dipropyl amine, isopropyl amine,ethanol amine, diisopropyl amine, butyl amine, dibutyl amine, hexylamine, Z-Ethylhexyl amine, N-methylbutyl amine, etc.

One of the utilities of the compounds of the process is exemplified bydata obtained using the product of Example 1 as the active ingredient.Herbicidal characteristics were determined by spraying the activematerial at.

a rate of 2 lbs./ acre using a water suspendible oil formulationthereof. In the table results are reported on a linear numerical scalewhere indicates no effect and indicates a complete kill (A) WeedsPigweed l0 Johnsongrass 9 Setaria 8 (B) Crops Corn 6 Oats 2 Wheat 1Another utility possessed by compounds which can be made using theprocesses of the instant invention arises in connection with thewilt-harvesting of cotton. Application of these materials to cottonprior to harvesting cause wilting of foliage to occur in a short timeand promotes boll opening. By harvesting cotton when the plant iswilted, yield and quality of cotton are improved. Further, thereafter,defoliation occurs and the balance of the cotton can be harvested. Allof these agricultural techniques are discussed at length in co-pendingapplication No. 632,937 referred to above. Sufiice it to say at thispoint, that it is commercially desirable for the compounds underconsideration to Wilt and/or defoliate cotton plants. Some test datademonstrative of this ability is given below in a series of testsperformed with the compound of Example 3 and various of its salts.Applications of the indicated compound at the rate of active ingredientshown 19 was in the form of a water extendible concentrate which wasdiluted to a spray volume equivalent to 20 gallons per acre.

Percent Percent wilt defoliation Rate (lbs./ 24 48 5 13 Compound ofacre)hours hours days days 1- Example 3 4 80 50 50 2. Ammonium salt 4 80 95 3Monomethyl amine salt 4 40 40 25 35 Monethyl amine salt 4 50 55 30 30 5Monoisopropyl amine salt. 4 55 70 20 2O 6- 'Irlethylarnine salt 4 40 505 5 7- Monoethanolamine salt 4 40 4O 25 25 8 Triethanolamine salt 4 2020 2 2 It has thus been demonstrated how methods of the inventionachieve the objects initially stated and produce compounds havingvarious agricultural utility.

Obviously, many modifications and variations of the invention, ashereinbefore set forth, may be made Without departing from the spiritand scope thereof. Therefore, only such limitations should be imposed asare indicated in the appended claims.

We claim:

1. A method for producing C to C polychlorinated or polybrominated4-keto-alkenoic acids, which comprises the steps of direct combinedcatalytic halogenation and dehydrogenation of C to C 4-keto monocarboxyalkanoic acids with elemental chlorine or bromine in the presence of acatalyst amount of at least one cation selected from the groupconsisting of aluminum, zinc, titanium, cobalt, magnesium and calcium,wherein the reaction is initiated at substantially ambient temperatureand during said time period the temperature is gradually raised to afinal temperature of from C. to 210 C., the reaction being controlled bythe rate of chlorine or bromine suflicient to prevent the temperatureexceeding 210 C.

2. The method of claim 1 wherein the catalyst is aluminum.

3. The method of claim 2 wherein the catalyst is introduced as A101 4.The method of claim 7 wherein the catalyst is magnesium.

5. The method of claim 4 wherein the catalyst is introduced as Mgcl 6.The method of claim 1 wherein both halogens are utilized successively asreactants.

7. The method of claim 1 wherein the final temperature is from C. to 210C.

8. The method of claim 1 wherein the starting alkanoic acid is levulinicacid, the halogen is chlorine gas and the final reaction productcontains a preponderance of tetrachloro-4-keto pentenoic acid.

9. The method of claim 1 wherein the starting alkanoic acid is levulinicacid, the halogen is chlorine gas and the final reaction product is2,3,5,5,5-pentachloro-4-keto pentenoic acid.

References Cited UNITED STATES PATENTS 2,557,779 6/1951 Britton et al.260539 R 2,985,684 5/1961 Pennino 260539 R 3,275,503 9/1966 Herschler260317 DONALD G. DAUS, Primary Examiner A. M. T. TIGHE, AssistantExaminer US. Cl. X.R.

1. A METHOD FOR PRODUCING C5 TO C10 POLYCHLORINATED OR POLYBROMINATED4-KETO-ALKENOIC ACIDS, WHICH COMPRISES THE STEPS OF DIRECT COMBINEDCATALYTIC HALOGENATION AND DEHYDROGENATION OF C5 TO C10 4-KETOMONOCARBOXY ALKANOIC ACIDS WITH ELEMENTAL CHLORINE OR BROMINE IN THEPRESENCE OF A CATALYST AMOUNT OF AT LEAST ONE CATION SELECTED FROM THEGROUP CONSISTING OF ALUMINUM, ZINC, TITANIUM, COBALT, MAGNESIUM ANDCALCIUM, WHEREIN THE REACTION IS INITATED AT SUBSTANTIALLY AMBIENTTEMPERATURE AND SURING SAID TIME PERIOD THE TEMPERATURE IS GRADUALLYRAISED TO A FINAL TEMPERATURE OF FROM 170*C. TO 210*C, THE REACTIONBEING CONTROLLED BY THE RATE OF CHLORINE OR BROMINE SUFFICIENT TOPREVENT THE TEMPERATURE EXCEEDING 210*C.